ly, the close relationship bet- Renewable Energy For Rural Development … · A. S. Sambo /ISESCO Science and Technology Vision - Volume 1 (May 2005) (12-22) 13 2. Some Major Energy

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V o l u m e 1 - M a y 2 0 0 5 ( 1 2 - 2 2 )

1. Introduction

Energy it is an essentialingredient for socio-econo-mic development and econo-mic growth. The objective ofthe energy system is to provi-de energy services. Energyservices are the desired anduseful products, processes orindeed services that resultfrom the use of energy, suchas for lighting, provision ofair-conditioned indoor clima-te, refrigerated storage, trans-portation, appropriate temperatures for cooking etc. Theenergy chain to deliver these cited services begins with thecollection or extraction of primary energy, which is thenconverted into energy carriers suitable for various end-uses.These energy carriers are used in energy end-use technologiesto provide the desired energy services (Sambo, 1997).

From the foregoing, it is clear that energy is an essentialinput to all aspects of modern life. It is indeed the lifewire ofindustrial production, the fuel for transportation as well as forthe generation of electricity in conventional thermal powerplants. The situation was such that nations were complacentwith the oil dominated scenarios of the 1950s and 1960sduring which time regular and reasonably cheap supplieswere available. However, oil producing countries caused aworld-wide reaction by deciding to increase the prices ofcrude oil in the early seventies. Of course, the oil-rich coun-tries like Nigeria recorded tremendous economic gains. Onthe other-hand, those developing nations that did not have oilwere subjected to serious economic problems as they sud-denly found themselves utilising, in some cases, up to 50% oftheir foreign exchange earnings for importing petroleum pro-ducts or crude oil in order to sustain their oil-based industriesand public utilities (Sambo, 1992).

Currently a high proportion of the world's total energyoutput is generated from fossil fuels such as oil and coal. Ingeneral, the quest for an option to conventional powerschemes for extension to remote and rural locations of deve-loping countries like Nigeria arises from the high costs asso-ciated with the extensions, as well as the maintenance, of thepower grid system to rural areas. The costs of grid extensionswill vary widely from country to country and will be heavilydependent on the system used, the length of connection requi-red, the type of topography, the usage pattern and the loadfactor of the supply point (Charters, 1985). More specifical-

ly, the close relationship bet-ween the proximity of energyresources to the potentialusers coupled with the highcost of conventional energysources have led to a consi-derable interest in the deve-lopment and application ofrenewable energy resources.Although research and deve-lopment activities are stillbeing seriously undertaken invarious aspects of renewableenergy utilisations, a number

of the technologies have since been shown to be feasible andready, for adoption into the economy. These technologies arevery suitable for the rural areas of Nigeria (Sambo, 1991).

It is now universally accepted that fossil fuels are finiteand it is only a matter of time before their reserves becomeexhausted. Estimates of reserves of fossil fuels all reach thesame conclusion. Extended use of these reserves, worldwide,in the current manner will continue for no more than somedecades to come. The need for supplementary or even alter-natives that ideally will be non- depletable energy sourceshave since been recognised. These non-depletable sourcesare replenishable and are also referred to as renewable ener-gy sources as they are available in cyclic or periodic basis.These include: Solar energy which has an estimated world-wide average power potentials of 24W per square metre ofthe earth's surface (assuming 10% efficiency); hydropower,major sources of which are still underdeveloped, has an esti-mated potential of the range 2-3TW with an annual output of10,000-20,000TWh but is only available in certain areas ofthe world; also available in limited areas of the world arewind energy and biomass (Considine, 1977).

The purpose of my presentation is to highlight the role ofrenewable energy for the rural development of Nigeria. Thepaper will review the current level of the use of renewableenergy systems and thereafter put forward necessary policymeasures that are essential in order to promote the use of thetechnologies. Section 2 of the article will look at some majorenergy issues in Nigeria. Sections 3; 4; 5; and 6 will respec-tively focus on renewable energy resource availability inNigeria; renewable energy for rural development; applica-tions of renewable energy in Nigeria; necessary measures forpromotion of renewable energy. The conclusions made arepresented in section 7.

Renewable EnergyFor Rural Development : The

Nigerian Perspective

A. S. Sambo

Abubakar Tafawa Balewa University, P.M.B. 0248

Bauchi, Nigeria

A. S. Sambo /ISESCO Science and Technology Vision - Volume 1 (May 2005) (12-22)

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2. Some Major Energy Issues In Nigeria

The major energy issues in Nigeria can be convenientlycategorised as inefficient energy utilisation, inefficient andunreliable energy supply system, environmental concerns,energy financing, inadequate technological capabilities in theenergy sector and weak institutional framework (World Ener-gy Council, 1993). However before discussing these issuesthere is need to consider the current energy consumption pat-terns of the country.

Energy Consumption Patterns

In 1991 the Sokoto Energy Research Centre, at the ins-tance of the Energy Commission of Nigeria, carried out a sur-vey of 55 Local Government areas in Niger, Kano, Katsinaand Sokoto States as well as in the Federal Capital Territory,Abuja. The report of that survey (Sambo, 1991) as well as thereport of similar surveys carried out in other parts of thecountry can be summarised as follows:

(a) Agricultural sector

Human and animal power provide the bulk of the energyrequirements for agricultural production. An assessment ofthe energy unit adopted, that is manhours, showed that sharpvariations exist in the magnitudes of the manhour figuresfrom place to place. Evidence of use of petroleum productsfor agricultural production has been recorded. This, thoughsmall when compared with human and animal power, issignificant because it showed the use of motorized irrigationpumps and diesel powered tractors for mechanised agricultu-ral activities.

(b)Household sector

Fuelwood was found to be the predominant energy sour-ce in the household sector with about 70 - 80% of householdsdepending on it as their cooking fuel in both the remote vil-lages and the towns. The consequence of this to the naturalenvironment is that unchecked felling of trees to provide thefuelwood requirements will exacerbate desert encroachment,soil erosion and loss of soil fertility problems. In the interimit would not be practical to stop the use of fuelwood rather theshort term solution is the adoption of efficient wood-burningstoves together with the widespread establishment of fast gro-wing trees. In the long term one would suggest the introduc-tion of other fuels like LPG, kerosine and smokeless coal bri-quettes to replace the use of fuelwood.

Kerosine is the predominant energy source used in therural areas for lighting. There is strong evidence of the use ofsmall quantities of kerosine to assist the quick commence-ment of combustion of fuelwood. This is in addition to its usein the urban centres as a cooking fuel. The predominant typeof lantern used, is the wick-type which does not produce agood level of luminosity. The third energy type in terms ofsignificance in the household sector is electricity which ismostly limited to state and local government headquartersand some big towns. Most of the electricity in the rural areasis provided by the State Rural Electricity Boards.

(c) Industrial sector

Mains electricity from NEPA dominates the energy sup-ply for the industrial sector. This is supplemented by electri-city generating sets that are fueled by automotive gas oil (die-sel). High and low pour fuel oils are used in textile, cementand brick manufacturing plants. The foregoing is for largeindustries which are mostly located in the big cities andtowns. For the small towns and villages, the bulk of the small- scale industries are operated on diesel generators for bake-ries, small - scale steel works, small - scale ceramic/potteryworks etc. In these localities other small-scale activities likehandicraft, weaving etc. are based on human power.

(d) Transport sector

In the transport sector, prime motor spirit (petrol) is themajor fuel for saloon cars and the "small buses". For lorries,trucks and rail transport the predominant fuel is automotivegas oil (diesel) while for air transport the fuel is aviationkerosine. It has been estimated that 74% of the petroleumproducts demand of Nigeria is for the transport sector withonly 19% for the industrial sector. Of the amount of fuelconsumed in the transport sector, 50% is absorbed by passen-ger transport by air.

(e) Services sector

In remote rural areas, human power is used for water liftingfrom wells while in the big villages and many towns, dieselpowered pumping systems are relied upon to lift water fromboreholes. Hospitals and health centres in rural areas rely onboth REB-generated electricity and diesel generators for ligh-ting, sterilising of appliances as well as for storage of drugs andvaccines. Use is made of fuelwood and to a lesser extent LPG,for cooking. The situation in the health centres is very muchthe same in boarding schools, barracks and prison houses.

Inefficient Energy Utilisation

Presently, energy utilization in Nigeria is far from beingefficient. Apart from the direct loss due to energy wasted,using energy inefficiently has three major implications inNigeria. These are:(a) The investment in some energy supply infrastructure is far

in excess of what the energy demand is;(b) The environmental problems associated with energy utili-

zation are more aggravated due to large energy consump-tion; and

(c) Excessive energy consumption adds to the costs of goodsproduced especially in energy intensive industries likecement, steel works and refineries.

The potential for energy savings is substantial in the threemost energy consuming sectors of the economy namely hou-sehold, industry and transportation. In the household sector,for example, there is considerable energy loss due to the useof inefficient traditional three stone stoves with efficienciesof between 5 to 12%. Efficiencies three times that can beobtained. In the household sector substantial savings can bemade by simple switching over from incandescent bulbs tofluorescent lamps. In the industrial sector energy audit stu-


dies have shown that up to 25% of energy consumption canbe saved by adopting simple house keeping measures. Suchmeasures include putting off electrical machinery on no-loadcondition, plugging steam leaks and avoiding material was-tages. In the transport sector, major savings can be realisedby emphasising mass transit schemes.

The major barriers militating against the adoption of moreenergy efficient practices in Nigeria can be identified as fol-lows:(a) Lack of awareness of the potential and importance of

energy efficiency;(b) Lack of skilled manpower to carry out energy audit stu-

dies; and(c) Lack of awareness of potential alternatives such as rene-

wable energy technologies.

Inefficient and Unreliable Energy Supply System

In electric energy supply efficiencies of existing thermalplants are low. They are as low as 12% whereas efficienciesof up to 40% are attainable with modern technologies. Alsosubstantial electricity is lost during transmission and distribu-tion. These losses are sometimes more than 30% of the totalelectricity generated. Apart from these inefficiencies thereliability and availability of existing installed electric gene-ration system is low. There is the serious problem of powerunreliability over the years such that most industrial esta-blishments and upper income households instal very expensi-ve generating sets amounting to over half of the total instal-led grid capacity. This constitutes huge economic losses tothe Nigerian economy.

The major factors contributing to the above unreliabilityand inefficiency in the power sector are:(a) Frequent breakdown of generating plants and equipment

due to inadequate repairs and maintenance;(b) Lack of foreign exchange to purchase needed spare parts

on time(c) Obsolete transmission and distribution equipment which

frequently breakdown(d) Lack of skilled manpower; as well as(e) Inadequacy of basic industries to service the power sector.

In the petroleum sector, production, marketing and distri-bution system are often inadequate, inefficient and costly. Onthe production side, refinery capacity utilization is generallylow largely due to operation and maintenance problems.

Environmental Concerns

The major environmental problems related to energy pro-duction, distribution and consumption are deforestation, airand land pollution as well as flooding. Excessive fuelwoodconsumption arises due to population growth, low technicalefficiency of the traditional three stone stoves and the lack ofadoption of other sustainable cooking methodologies. Thesecontribute to deforestation which is a very serious issuebecause of the important roles forestry resources play in theecosystem. They serve as sinks for carbon dioxide, maintaindiverse plants and animal life and also regulate the flow ofwater. Their loss, as mentioned earlier, leads to soil erosion,desert encroachment and loss of soil fertility.

Combustion of fossil fuels, especially in the transport andindustry sectors, contributes greatly to air pollution in cities.A major air pollution that poses health hazards to both dwel-lers of the cities and rural areas is the long exposure to smokefrom biomass combustion in poorly ventilated kitchens.Major water and soil contamination are reported from time totime which arise from oil spillages in the oil producing areasof the country. Dams for hydropower have been noted to per-iodically cause flooding of agricultural land upstream whileat the same time the dams cause destruction of the ecologydownstream.

Other Issues

The other important issues include poor energy financing,low technical capabilities in the energy sector and weak ins-titutional framework. The energy sector is a large consumerof national resources, demanding large capital expenditures,skilled manpower and steady foreign exchange outflows.Almost invariably, energy financing has been the exclusiveprerogative of government whose own capacity to financenew investments is inadequate. Low technical capacity isresponsible for the nation's inability to manufacture compo-nents of power plants as well as to maintain the various unitsof the energy sector. The main problem with institutional fra-mework in the energy sector is the fact that the linkages bet-ween the various energy institutions are rather weak.

The Need to Re-address Our Priorities

An analysis of the country's energy resource base willclearly show that the nation stands to benefit immensely byensuring that petroleum products are made to last for as manyyears to come as possible so they continue to serve as revenueearners and also to enable fuelling of the industrial sector foras many years to come as possible. This can only be realizedafter the adoption of as many energy types as possible withinthe energy mix of the country. The clear and practical approa-ch is to adopt the renewable energy sources of solar, biomass,wind energy and small-scale hydropower plants for as manyapplications as possible. This approach is supported by thefact that all or at least two renewable energy sources are avai-lable in all parts of the country, the technology for their use ismostly simple and for which the capacities exist; their usedoes not require the heavy financing mentioned in 2.5 aboveand they are not associated with serious environmental impli-cations. As a matter of fact these considerations were longthought of and brought to bear by the Federal Governmentwhich established, amongst others, two energy researchcentres for research and development in renewable energy.

3. Renewable Energy Resource AvailabilityIn Nigeria

For the purpose of this presentation the renewable energysources that will be considered are hydro, solar energy, bio-mass and wind energy.

Hydro

Essentially, hydropower systems rely on the potentialenergy difference between the levels of water in reservoirs,

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dams or lakes and their discharge tail water levels downs-tream. The water turbines which convert the potential ener-gy of water to shaft rotation are coupled to suitable genera-tors. The hydropower potential of Nigeria is very high andhydropower currently accounts for about 29% of the totalelectrical power supply. The first hydropower supply stationin Nigeria is at Kainji on the river Niger where the installedcapacity is 836MW with provisions for expansion to 1156MW. A second hydropower station on the Niger is at Jebbawith an installed capacity of 540 MW. An estimate (Aliyu andElegba, 1990) for rivers Kaduna, Benue and Cross River (atShiroro, Makurdi and Ikom, respectively) indicates their totalcapacity to stand at about 4,650 MW. Estimates for the riverson the Mambila Plateau are put at 2,330MW. The overallhydropower resources potentially exploitable in Nigeria is inexcess of 11,000MW.

The foregoing assessment is for large hydro schemeswhich have predominantly been the class of schemes in useprior to the oil crisis of 1973. Since that time, however, manydeveloped and developing countries have opted for small-scale hydropower with appreciable savings made over theotherwise alternative of crude oil. It should be noted thathydropower plants that supply electrical energy between therange of 15kW to 15MW are mini-hydro while those sup-plying below 15kW are normally referred to as micro-hydroplants (Sambo and Taylor, 1990). Indeed small-scale (bothmicro and mini) hydropower systems possess the advantage,over large hydro systems, that problems of topography arenot excessive. In effect, small hydropower systems can be setup in all parts of the country so that the potential energy in thelarge network of rivers can be tapped and converted to elec-trical energy. In this way the nation's rural electrification pro-jects can be greatly enhanced.

Solar Energy

Solar energy is the most promising of the renewable ener-gy sources in view of its apparent limitless potential. The sunradiates its energy at the rate of about 3.8 x 1023 kW persecond. Most of this energy is transmitted radially as electro-magnetic radiation which comes to about 1.5kW/m2 at theboundary of the atmosphere. After traversing the atmosphere,a square metre of the earth's surface can receive as much as1kW of Solar power, averaging to about 0.5 over all hours ofdaylight. Studies relevant to the availability of the solar ener-gy resource in Nigeria (Sambo, 1986; Sambo, 1988; Sambo,Doyle, 1986; Doyle and Sambo, 1988; and Folayan, 1988)have fully indicated its viability for practical use. Althoughsolar radiation intensity appears rather dilute when comparedwith the volumetric concentration of energy in fossil fuels, ithas been confirmed that Nigeria receives 5.08 x 1012 kWh ofenergy per day from the sun and if solar energy applianceswith just 5% efficiency are used to cover only 1% of thecountry's surface area then 2.54 x 106 MWh of electricalenergy can be obtained from solar energy. This amount ofelectrical energy is equivalent to 4.66 million barrels of oilper day. Figure 1 shows a map of Nigeria with the annual ave-rage global solar radiation in the country.

Solar energy technologies are divided into two broadgroups namely solar-thermal and solar photovoltaics. In solarthermal applications, solar energy, as electromagnetic waves,is first converted into heat energy. The heat energy may thenbe used either directly as heat, or converted into 'cold', oreven into electrical or mechanical energy forms. Typical suchapplications are in drying, cooking, heating, distillation,cooling and refrigeration as well as electricity generation inthermal power plants.

In solar photovoltaic applications, the solar radiation isconverted directly into electricity. The most common methodof doing this is through the use of silicon solar cells.

The technique was first observed in 1939. Its develop-ment had been closely tied to the space programme of thewestern world. The power generating unit is the solar modu-le which consists of several solar cells electrically linkedtogether on a base plate. On the whole the major componentsof a photovoltaic system include the arrays which consist ofthe photovoltaic conversion devices, their interconnectionsand support, power conditioning equipment that convert thedc to ac and provides regulated outputs of voltage and cur-rent; controller, which automatically manages the operationof the total system; as well as the optional storage for stand-alone (non-grid) systems. In recent times, the commercialviability of photovoltaic systems have been recognized andconcerted international efforts in research and developmenthave led to increase in efficiency and reliability as well asreductions in cost.

Biomass

Biomass energy refers to the energy of biological systemssuch as wood and wastes. Biomass energy is an indirect form ofsolar energy because it arises due to photosynthesis. The bio-mass resources of Nigeria can be identified as wood biomass,forage grasses and shrubs, residues and wastes (forestry, agricul-tural, municipal and industrial) as well as aquatic biomass.

Wood, apart from being a major source of energy in theform of fuelwood is also used for commercial purposes invarious forms as plywood, sawnwood, paper products andelectric poles. For energy purposes, Nigeria is using 80 mil-lion cubic metres (43.4 x 109 kg) of fuelwood annually forcooking and other domestic purposes. The energy content offuelwood that is being used is 6.0 x 109MJ out of which onlybetween 5 - 12% is the fraction that is gainfully utilized forcooking and other domestic uses. Although the biomass avai-lability as at 1973 was put at 9.1 x 1012 MJ, it is expected thatthe overall biomass resource availability at present is lowerthan the 1973 figure. This is largely due to the demand ofwood also for construction and furniture industries in addi-tion to its use as an energy source. As for forage grasses andshrubs, estimates show that 200 million tonnes of dry bio-mass can be obtained from them and this comes up to 2.28 x106MJ of energy.

For crop residues and wastes, estimates of the 6.1 milliontonnes of dry biomass that are produced annually leave resi-dues whose energy content approximate to 5.3 x 1011 MJ.

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Estimates made in 1985 give the number of cattle, sheep,goats, horses and pigs as well as poultry birds as 166 million.These produce 227,500 tonnes of animal wastes daily whichcome to 2.2 x 109 MJ taking the calorific value of animaldung to be 9,800 MJ/tonne. Animal residue can be convertedto biogas and estimates show that this is of the order of 5.36x 109 m3 which has an energy content amounting to 2.93 x109 kWh.

Wind Energy

Wind is a natural phenomenon related to the movement ofair masses caused primarily by the differential solar heatingof the earth's surface. Seasonal variations in the energy recei-ved from the sun affects the strength and direction of thewind. The ease with which aeroturbines transform energy inmoving air to rotary mechanical energy suggests the use ofelectrical devices to convert wind energy to electricity. Windenergy has also been utilised, for decades, for water pumpingas well as for the milling of grains.

A study on the wind energy potentials for a number ofNigerian cities shows that the annual wind speed ranges from2.32 m/s for Port Harcourt to a figure of 3.89 m/s for Sokoto(Sambo, 1987). The maximum extractable power per unitarea, for the same two sites was estimated as 4.51 and 21.97watts per square metre of blade area, respectively. And whenthe duration of wind speeds greater than 3 m/s is consideredthan the energy per unit area works out as 168.63 and1,556.35 kWh per square metre of blade area, again for Port-Harcourt and Sokoto.

Although use of wind energy for water supply has beenknown and used for hundreds of years, in recent times effortshave been directed largely towards the use of wind power forthe generation of electricity and in the past twenty years or sorapid changes in technology have occurred and major windpowered generating plants have been installed, especially inthe rural areas of the developed countries.

4. Renewable Energy Systems For RuralDevelopment

In this section of the paper it is intended to cover the ener-gy needs in rural areas as well as the basis for design of solarand wind energy systems.

Energy Needs in Rural Areas

In general, the energy needs in the rural and semi-urbanareas of Nigeria can be categorized as follows:

A. Domestic Needs- Cooking- House lighting- Domestic water pumping and distribution- Television and radio powering- Water heating- Refrigeration

B. Agricultural Production- Water pumping and distribution for irrigation- Operation of various agricultural equipment or implements

- Processing and storage of agricultural products- Drying

C. Community Needs- Hospitals, Clinics- Schools- Barracks, prison houses etc.

D. Industrial/Commercial Needs- Small to medium industries- Business establishments (shops, banks, restaurants, bake-

ries etc).

Basic Principles for Design of Renewable Ener-gy Systems

Due to the large variety of biomass devices the basicconcepts for their design also vary widely. This is largely dueto the nature of biomass itself as discussed in section 3.3above. Accordingly this section will focus attention on solarand wind energy principles only.

A. Basis for Design of Solar Energy Systems

The utilisation of solar heat collection systems for produ-cing electrical or mechanical power using thermodynamicheat engines has been confirmed to be technically feasibleand a large number of real life systems have been constructedin several countries. However, the use of solar energy forpower production, and for the development of both small andlarge scale solar thermal power systems, the actual costs ofenergy are high and for the systems cannot compete in heavi-ly populated urban cities or areas serviced by a central ornational grid electrical power distribution system. However,in most rural areas where the costs associated with providingpower may be five to fifty times of those in metropolitanareas, solar thermal power generation schemes are alreadycost effective.

The essential parts of any solar thermal power generatingscheme are as follows:- A means of solar energy collection- Provision of suitable thermal/mechanical converter and

mechanical/electrical converter- A method of storing energy for use in non-solar or low solar

periods

The available solar collector systems may be broadlyclassified as flat-plate and concentrating collectors. Concen-trating collectors which are usually employed for high tem-perature applications often require serious attention for theiroperation. The more straight forward arrangement is the flat-plate collector which is more appropriate for rural areas. Thebasic components of flat-plate solar collectors are an absor-bing surface which receives insulation and an air duct oneside of which is formed by the absorber to reduce losses fromthe absorber and insulation. For applications requiring highair or liquid flow, an air fan or liquid pump is used to blow airor liquid through the collector.

Factors affecting the amount of useful energy absorbed bythe absorber plate of a flat-plate collector are: level of insula-tion, angle between incident insolation and the absorber platesurface, the solar absorptivity of the cover material.

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Indeed flat-plate collectors are well adapted to applica-tions requiring low to medium temperature rise of the wor-king fluid, such as in crop drying, water heating, and vapourabsorption refrigeration systems. The use of flat-plate col-lectors in crop drying and water heating have been found tobe more cost effective when compared with conventionalmethods using gas, oil or electric heaters. Solar crop dryersand solar water heaters are highly recommended.

As mentioned in section 3.2 the direct conversion of solarradiation to electricity is achieved through the use of solarcells which are fabricated from single crystal, polycrystallineor amorphous silicon and are usually mounted in a solar cellmodule to produce reasonable peak power output level underconditions of maximum solar radiation. The direct current(d.c.) output voltage per cell is typically of the order of 0.5volts and the output current is governed primarily by the cellarea and intensity of the sunlight. The modules may be wiredtogether to form solar cell arrays designed to match thepower, voltage and current requirements. The output of amodule is well matched to the task of battery charging sinceit is the current rather than voltage that varies with solarradiation intensity.

The d.c. power from solar module can be used to powerlights, electric motors and other resistive loads. Most sys-tems employ a voltage regulator to protect the battery andload appliances from excessive over-voltage conditions. Thisregulator is connected between the battery and the array anddissipates any excess energy when the battery bank is fullycharged. A d.c. circuit also includes a blocking diode bet-ween the array and the battery to prevent a current flow atnight from battery to the solar photovoltaic module array.Alternating current (a.c.) power is now most commonly usedas in addition to lights and other resistive loads, it is requiredto power the cheap induction electric motors found in a widevariety of appliances. To produce a.c. power from the d.c.solar cell output an inverter is placed in the circuit before theload. Such an inverter will produce a wave form approxima-ting a sine wave with varying degrees of distortion dependingon the quality and cost of the inverter chosen. In general,inverters should be carefully chosen to match, closely, thepower demand of the load.

B. Basis for Design of Wind Energy Systems

The use of wind energy to provide power for a host ofpurposes has been known to man for hundreds of years espe-cially for water pumping. In recent times, efforts have beendirected towards the use of wind power for the generation ofelectricity and in the past twenty years or so rapid changes intechnology have occurred and major wind powered genera-ting plants have been installed, especially in rural areas. Allwind generators convert the kinetic energy of the wind intomechanical power at some rotating shaft and then, if so desi-red, to electrical power through a generator. Generally, com-mercial wind machines can be classed as small ranging froma few watts to 10kW, medium from 10-60kW, and large from60kW-300kW. In addition, there are some very largemachines with power outputs in excess of 1MW at severalsites throughout the world.

Modern aerogenerators that produce a.c. electricity comein two basic types - horizontal or vertical axis machines.Most of the available commercial machines are of the hori-zontal type, and the number of blades chosen for thesemachines is a compromise between high self starting ability(indication of good performance at low wind speeds) andgood efficiency at higher operational seeds. Some verticalaxis machines are now commercially available, but theygenerally have lower conversion efficiencies than their hori-zontal axis counterparts. Vertical axis machines have theadvantages of the ability to operate with wind from any direc-tion, and reduced power costs as the heavier equipment itemssuch as gearbox and transmission can be ground mounted.

At any location of choice it is possible to compute themaximum power output from a wind turbine by knowing theaverage wind speed distribution and the technical characte-ristics of the wind system prescribed.

5. Applications Of Renewable Energy Tech-nologies In Nigeria

In Nigeria, as a result of research and development acti-vities that have been undertaken in our Universities and Poly-technics a large number of renewable energy systems anddevices have been developed and a good number are indeedready for adoption into the national economy. A report com-piled by the Sokoto Energy Research Centre in 1991 (Sambo,1991) provides details of the technologies that were develo-ped at the Centre and which were ready for adoption into theeconomy. A more comprehensive compilation of the status ofrenewable energy technologies is the book "POTENTIALSFOR RENEWABLE ENERGY APPLICATION IN NIGE-RIA" which was published in May 1997 by the Energy Com-mission of Nigeria.

5.1 Major Applications of Renewable EnergySystems

A. Solar Energy

There are many solar thermal systems especially solarwater heaters and solar dryers in use in many parts of thecountry. Solar cookers, solar stills, solar chicken broodersand solar thermal refrigerators developed by research centresand confirmed to be of practical applications.

However solar photovoltaic applications have wider cur-rent installation in the country and these include solar photo-voltaic water pumping systems, solar powered vaccine refri-gerators as well as telecommunication repeater stations thatare powered by solar photovoltaics. There are also solar pho-tovoltaic power plants that are providing electricity to entirevillages and also others that are powering on stand-alonebasis, some specific projects such as rural health centres tele-vision viewing centres.

B. Biomass

Many versions of efficient wood-burning and charcoalstoves have been developed and are being used in many partsof country with the overall objective of curtailing the amounttrees that are perennially cut to provide fuelwood and char-

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coal. Biogas digesters, which are capable of producing bio-gas that could be used for domestic and industrial uses, havebeen developed in many parts of the country.

C. Wind Energy

Wind energy used to be relied upon in the 1950s and1960s for provision of water in many locations of the nor-thern part of the country. However this was largely abando-ned when the development of petroleum products reachedadvanced stages. The development of the Poldow wind pumpin Bauchi using locally available materials is surely a movein the right direction. Of course it should be mentioned thatthere a few modern wind water pumps in some parts of thecountry. There is also one wind electricity generator current-ly supplying electricity from wind energy at Sayya GidanGada in Sokoto State.

Renewable Energy Technologies Ready for LocalAdoption

A large number of renewable energy devices have beendeveloped by Nigerian researchers in various parts of thecountry (Sambo, 1991). These devices which are ready forincorpation into the economy especially for rural areas inclu-de (pictorial representation of these systems are provided inthe appendix):

A. Solar Cookers

These are box-type arrangements where most local dishescan be cooked within one hour under average sunshine condi-tions.

B. Solar Water Heaters

The heaters which are based on flat-plate collectors withappropriate storage units can produce water at temperaturesof up to 80oC will find applications in hospitals, hotels,industry and private residences and are capable of significantreduction of electricity bills.

C. Solar Dryers

Both portable cabinet dryers, for individual private use, aswell as large-scale units, for community utilisation, havebeen developed. The dryers which typically attain tempera-tures of up to 60-70°C are suitable for drying a variety ofagricultural produce.

D. Solar Stills

Solar stills are designed to produce distilled water frombrackish water and will be useful for hospitals, industry andlaboratories. When sized appropriately they can provide forthe needs of comprehensive health centres of semi-urbanlocalities.

E. Water Pumping

Many workers have demonstrated the use of photovoltaicsolar modules for pumping water from wells and boreholesespecially in rural areas for providing the water requirementsof entire communities. Photovoltaic powered pumps can alsobe employed for irrigation purposes.

F. Storage of Vaccines and Drugs

Photovoltaic power components have also been shown toadequately provide the electricity for refrigerators and deepfreezers in which vaccines and drugs can be safely storedwithout loosing their potencies.

G. Street Lights and Traffic Controllers

Photovoltaic modules have been used to provide uninter-rupted electricity during the day and night for traffic control-lers in city centres. With the use of storage batteries theyhave also been shown to power street lights continuouslywithout the power outages commonly associated with themains supply.

H. Improved Wood-Burning Stoves

Clay-based improved cookstoves, of various designed,have been developed and these conserve the amount of fuel-wood consumed by up to 50%, lead to faster cooking andwith the attachment of chimneys they allow for organised exitof smoke and consequently reduce smoke inhalation.

I. Production of Biogas

With biogas digesters, which are typically constructedfrom sheet metal or empty drums and fed with slurries of ani-mal dung they can produce biogas and after 2-3 days. Thisgas which has a reasonable content of methane is combustibleand can be relied upon for the production of gas for domesticcooking. It can also be used for powering internal combus-tion engines for electricity generation in rural areas.

J. Wind for Electricity Generation

In Nigeria, for quite some time, only laboratory trialshave been made in the area of using wind for electricity gene-ration. Such trails have been made with models of three-bla-ded aeroturbines and the results obtained indicate the poten-tial for stand-alone utilisation especially in the Sahelian zoneas well as the coastal areas of the country. Recently, howe-ver, an increasing number of wind water pumping sets andwind electricity conversion systems have been installed.

K. Electricity from Microhydro Systems

The generation of electricity from numerous waterfallsand rivers in the form of microhydro plants for integrationinto the national grid as well as for stand-alone utilisations, inremote locations, is a system that has been shown to be viable.

Renewable Energy Systems Installed for Com-munity Utilisation

Over the past 13 years the Energy Commission of Nige-ria, some state governments, the Education Tax Fund and afew other organisations have sponsored the installation ofmany pilot renewable energy systems for use by various com-munities. All the projects under reference have been execu-ted by the Sokoto Energy Research Centre and quite a num-ber of them are in Niger, Cameroun and Chad Republics.Table 1 shows the list of 11 such projects on electrificationwhile Tables 2 and 3 respectively provide data on 17 photo-voltaic water pumping and 14 solar thermal/biogas systems.

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TABLE 1: LIST OF PHOTOVOLTAIC ELECTRIFICATION SYSTEMSINSTALLED BY SOKOTO ENERGY RESEARCH CENTRE

S/N TYPE OFAPPLICATION

1. ELECTRIFICATION

2. ELECTRIFICATION

3. COMMUNICATION& ELECTRIFICATION




7. ELECTRIFICATION

8. ELECTRIFICATION

9. ELECTRIFICATION

10. ELECTRIFICATION

11. ELECTRIFICATION(WIND ENERGY)

LOCATIONDATE OF INST.

SERC 1992

Kwalkwalawa 1994

1 Div. Hq.Kaduna 1998

3 MechanizedBrid. Kano 1999

Giginya BarracksSokoto, 1999

Minna Barracks 1999

Agbashi Nassarawa.1999

UDUS, City Campus,2002

UDUS, NUNET, 2002

School for theDeaf, Kaduna, 2003

Sayya Gidan-Gada 1998

POWERRATING IN kW

4.5

7.2

1.5

1

1

1

2.5

1.5

2

5

5

TYPE OFINVERTER

1 Nos of 2.5kW

4 Nos of 2.5kW

2 Nos of 1.kW &500W

2 Nos of 500W

2 Nos of 500W

1 No. of 1kW

1 No. of 3kW

1 No. of 1.5kW

1 Nos of 2kW

2 Nos of 3kW

2 Nos of 2.5kW

SPONSOR

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Education Tax Fund

Usmanu DanfodioUniversity, Sokoto

Education Tax Fund

Energy Commission

TABLE 2 : LIST OF PHOTOVOLTAIC WATER PUMPING SYSTEMS INSTALLEDBY SOKOTO ENERGY RESEARCH CENTRE

S/NLOCATIONSPONSOR & DATE

1. Mech. Workshop, UDUS (1992)

2. Kalgo ((Binji) 1995

3. Ruggar Kijo (Yabo) 1996

4. Yar Tsakwa (Rabah) 1997

5. Falale (Gummi) 1998

6. Bukkuyum (Zamfara State)

7. Danzabuwa (Kano) 1998

8. Nangere (Yobe) 1997

9. Gumel (Jigawa) 1998

10. Kadar Tsaka (Sokoto) 1999

11. Birnin Tsaba (Zamfara)

12. Kuruwa (Sokoto) 1998

13. Achida (Sokoto) 1999

14. Kebbe (Sokoto) 1999

15. Goronyo (Sokoto) 1998

16. F. G. C. Kwali, Abuja (Feb., 2003)

17. Students’ Hostel UDUS (Feb., 2003)

TYPES OFMODULES

SEIMENS M55

SEIMENS M55

SEIMENS M55

SEIMENS M55

ARCO M90

ARCO M60

SEIMENS M55

SEIMENS M55

ARCO M90

SEIMENS M55

SEIMENS M55

SEIMENS M55

SEIMENS M55

SEIMENS M55

SEIMENS M55

Isofotons M55

Isofotons M55

TOTAL

42

79

65

70

22

75

71

70

70

80

70

69

110

40

52

52

60

HEAD INMETERS(m)

35

18

20

20

35

20

18

20

20

20

20

20

20

18

20

20

20

DISCHARGEin m3/day

Energy Commission

Sokoto State Govt.

Sokoto State Govt.

Sokoto State Govt.

Zamfara State Govt.

Zamfara State Govt.

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Zamfara State Govt.

Sokoto State Govt.

Sokoto State Govt.

Sokoto State Govt.

Sokoto State Govt.

E T F

E T F


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TABLE 3 : LIST OF SOLAR THERMAL & BIOGAS SYSTEMS INSTALLEDBY SOKOTO ENERGY RESEARCH CENTRE

S/N TYPE OF PROJECT

1.Improved Wood Stove

2.Multi-booster Forage Solar Dryer

3.Multi-booster Forage Solar Dryer

4. Biogas Plant

5. Biogas Plant

6. Solar Water Heater

7. Improved Wood Stove

8. Biogas Plant

9. Biogas Plant

10. Biogas Plant 4 Nos

11. Biogas Plant

12. Biogas Plant

13. Biogas Plant

14. Biogas Plant

LOCATION & DATE

Danjawa (Sokoto), 1988

NAPRI (Zaria), 1996

New-Bussa & Yauri, 1997

NAPRI (Zaria), 1996

Zaria Prison, 1998

UDUTH (Sokoto), 1997

Zaria, Sokoto, Kebbi & Zamfara Prisons, 1998

Mayflower Sch. Ikene(Ogun State), 2001

Ojokoro, Lagos, 2001

Mega-chad Maiduguri, 2003

Maiduguri, 2000

Chad Republic, 2003

Cameroun, 2003

Niger Republic, 2003

SIZE OF PROJECT/CAPACITY

200 Nos

2 tonnes/day

1 tonne/day

20m3

20m3

1000 Litres

150-200 Nos

20m3

20m3

20m3

20m3

8m3

8m3

8m3

SPONSOR

Fed. Min. of Sci. & Tech.

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Energy Commission

Energy Commission

University of Maiduguri

Al Amin Daggash

Mega-Chad Project

Mega-Chad Project

Mega-Chad Project

6. Necessary Measures For Promotion Of Rene-wable Energy For Rural Development Of Nigeria

With the availability of renewable energy resources in allparts of the country and the existing level of development ofsystems and devices in the nation, there is the urgent need forall of us to adopt practical measures that will systematicallyintroduce various renewable energy technologies into the eco-nomy. Apart from the policy measures that will promote theintroduction of technologies based on individual renewableenergy sources there is also the need to adopt an integratedapproach to sustainable energy development. This is in reco-gnition of the fact that conventional energy sources will conti-nue to serve the transport and industrial sectors of the economy.

Policy Measures for the Various RenewableEnergy Technologies

(a) Solar Energy

The thrust of the policy here should be the incorporationof solar energy devices into as many spheres of the economyas possible. The strategy for this include:- continuous active support of research and development acti-

vities to cater for site specificity of designs for all parts ofthe country.

- support of demonstration and pilot projects to ensure thatthe general public become aware of the potentials of solarenergy technologies which will as well assist in creation ofmarkets for solar energy systems

- the provision of financial incentives to encourage the use ofsolar energy systems particularly in rural areas where thegreatest potential exist

- the introduction of regulatory measures to encourage andprotect local capabilities.

(b) Biomass

The policy outlined above for solar energy also applieshere. Further it should be emphasized that fuelwoodconsumption rate should be significantly reduced. Strategiesfor this are:- the adoption of efficient wood - burning stoves- systematic cultivation of fast growing trees needed to faci-

litate the regeneration of forests- the active introduction of biogas digesters to cater for the

cooking energy needs of especially large households andinstitutions like boarding schools, hospitals, barracks, pri-son houses etc.

- the development of alternative technologies to supplementwood both as a domestic energy source and also as a buil-ding/furniture material.

(c) Wind Energy

The policy and strategies for solar energy are also appli-cable here. Additionally, the policy should emphasize theexploitation of wind energy for rural water supply and alsofor electricity generation. That is to say the additional strate-gies are:- aggressive drive to optimize the components of wind water

pumping and electricity generation and - to de-emphasizediesel powered water pumps wherever the wind speed willallow wind water pumping.


(d) Hydropower

The policy here is for the nation to manage its waterresources for the development of its hydro - electric potentialsand for other uses. The policy should focus more on micro-hydro plants. The additional strategy includes the initiatingand updating of data on the potentials of small - scale hydro-plants and the preparation of inventories for their locations.

Integrated Approach to Sustainable EnergyDevelopment

While section 5.1 above is aimed at policies to enable the adoption of renewable energy technologies, this section willfocus on what is necessary in order to address the generalenergy issues raised in section 2. The agenda for solvingthese general energy problems include the promotion of ratio-nal and efficient energy use, to guarantee energy security forthe rural populace, to create an enabling environment toattract investments in the energy sector, the integration ofenvironmental considerations into energy development plansand the strengthening of technical capacities in the energysector.

(a) Promotion of rational and efficient energy use

To achieve a more rational and efficient energy utilizationwe must ensure that wastages in energy use are reduced, ener-gy efficiencies of major energy supply systems are improvedconsiderably and a more energy efficient development path ispursued. For these to be realised the following strategies arerequired:- creation of awareness for the benefits of energy savings in

all sectors of the economy.- encouraging households to shift to more energy efficient

fuels such as LPG to kerosine in place of fuelwood.- promoting the use of improved cooking stoves.- providing incentives for energy intensive industries to

invest in industrial energy efficiency measures and humanresources development in the area of energy conservation.

(b) Provision of energy security for rural dwellers

One of the major needs of rural dwellers is the energythey consume for subsistence and because they lack access tocommercial fuels like petroleum products and electricity theydepend largely on traditional fuels mainly fuelwood, charcoaland agricultural residues. In order to provide the energyneeds of rural dwellers, especially in the Sahelian zone of thecountry, the following measures are necessary:- continued afforestation programme- setting up of community based woodlot programmes- accelerated rural electrification schemes- promotion of energy efficiency practices.

(c) Creation of enabling environment to attract invest-ment in the energy sector

Investment requirements for the conventional energy sec-tor is large and it is clear that government will not be able tosolely finance the sector as has been the case in the past.Hence private sector participation is necessary. Therefore,there will be need to attract foreign investment in the sector.

The needed attractions include the serious improvement inthe financial performance of the conventional energy supplycompanies as well as the existence of conducive investmentenvironment. On the whole, attention of private sector invest-ment will call for:- reviewing existing energy pricing to allow for good returns

on investments;- easing the difficulties in the procurement of foreign exchange- promoting energy conservation and efficiency measures in

all sectors of the economy;- maximising the operating performance of existing energy

supply infrastructure.

(d) Integration of environmental consideration intoenergy development plan

Because of the strong energy - environment linkage it isimportant to integrate the policies affecting the two sectorsfor sustainable development. This can be done by incorpora-ting environmental considerations during the planning andexecution stages of large conventional energy projects. Therequirements for this include:- improving forestry management by strengthening the insti-

tution charged with monitoring forestry resources;- incorporating environmental impact assessment for all

major energy projects;- internalizing the external cost in pricing energy products- designing and enforcing guidelines for monitoring the envi-

ronment.

(e) Strengthening technical capacities in the energy sector

Two major steps are required here. These are firstly, theoffering of specialized training and development of soundtechnical education in the educational system and secondly,to ensure that the available pool of human resources are giventhe opportunities to "learn - by - doing". Another requirementfor strengthening technical capabilities is the strengthening ofresearch, development and demonstration activities in theenergy sector. Of course the acquisition of technology deve-loped elsewhere and adapting them for use in Nigeria is a keyelement here. We can therefore list the strategies for streng-thening technical capacities as follows:- provision of technical support services needed for the effec-

tive training of personnel- subsidizing the cost of technical education- mobilizing local expertise and involving them in the plan-

ning, designing and construction of energy projects so theycan "learn - by - doing".

- provision of adequate funding for energy research, develop-ment and demonstration activities.

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7. Conclusions

Nigeria is blessed with abundant resources of fossil fuels as well as renewable energy resources. There is the urgent need toencourage the evolvement of an energy mix that will emphasize the conservation of petroleum resources in such a mannerthat will lead to their continued exportation for foreign exchange earnings for as many years to come as possible. The adop-tion of renewable energy technologies especially for rural development will surely lead to reduced internal consumption ofpetroleum products.

The major advantages of the renewable energy technologies include the simplicity of the technologies, ease of maintenanceas well as their enhanced environmental friendliness over fossil fuel systems.

There is clear evidence of the use of renewable energy technologies at the moment. However there is the necessity to increa-se the use of the system especially for rural development. In this regard there is the urgent need for more support of resear-ch, development, demonstration and diffusion activities in the existing research centres as well as identified groups in otherinstitutions. Indeed energy extension outfits will have to be established. While the existing research centres should be sup-ported adequately to carry out quality research and development activities, the energy extension centres should be mandatedto carry out demonstration and diffusion activities. In view of the apparent reluctance of local entrepreneurs to adopt themature and proven renewable energy systems for mass production and subsequent commercialization there is need to acti-vely promote the training of local craftsmen on the design, construction, operation and maintenance of appropriate energyend - use devices. After such training programmes soft loans could be made available to the craftsmen so they can commencethe production and subsequent sale of the devices.

All the aforementioned policy measures and implementation strategies to promote the use of the sustainable energy systemsand practices can only be realised with strengthened energy institutions. In this regard there is the need to identify organi-sations or offices at states and local government levels that will be charged with the responsibilities of ensuring the full imple-mentation of projects and programmes of the Energy Commission of Nigeria at the grassroots levels. Of course the muchawaited National Energy Policy for the country should be approved and released by the Federal Government.

ReferencesAliyu, U. O. and Elegba, S. B. (1990): 'Prospect for small hydropower develop-ment for rural applications in Nigeria', Nig. Journal of Renewable Energy,Vol.1,Pp.74 - 86.

Boyle, G. (1996): Renewable Energy-Power for a Sustainable Future. OxfordUniversity Press

Charters, W.W.S. (1985): Solar and Wind Power Technologies for Remote Appli-cations. CSC Technical Publication Services No.187, Commonwealth ScienceCouncil.

Considine, D.M. (Ed) (1977): Energy Technology Handbook. McGrawhill BookCompany.

Doyle, M.D.C. and Sambo, A.S. (1988): 'Correlation of diffuse solar radiationwith air mass', Solar and Wind Technology, Vol.5(1), Pp.99 - 102.

Energy Commission of Nigeria (1997): Potentials for Renewable Energy Appli-cation in Nigeria. Gilspar Col. Ltd., Lagos.

Folayan, C.O. (1988): 'Estimate of global solar radiation bound for some Nigeriancities', Nigerian Journal of Solar Energy, Vol.7, Pp.36 - 48.

Sambo, A. S. (1997): “Energy options for sustainable national development:Resources, issues, and the position of renewable energy technologies”, Universi-ty Inaugural Lecture delivered on 17th January, 1996, Published as Inaugural Lec-ture Series No. 1, ATBU Ceremonies, 1997.

Sambo, A.S. (1986): 'Empirical Models for the correlation of global solar radia-tion with meteorological data for northern Nigeria', Solar and Wind Technology,Vol.3(2), Pp.89 - 93.

Sambo, A. S. (1987): 'Wind energy assisted solar electricity generating schemesfor the rural areas of Nigeria', Large Scale Systems in Developing Countries(Ovuworie, G.C., Onibere, E.A. and Asalor, J.O. (Eds.)), Pp.45 - 160, Joja Educ.Research and Pub. Ltd.

Sambo, A. S. (1988):'The measurement and prediction of global and diffuse com-ponents of solar radiation for Kano in Northern Nigeria', Solar and Wind Techno-logy, Vol.5(1), Pp. 1 - 5.

Sambo, A. S. (1991): Sokoto Energy Research Centre, Usmanu Danfodiyo Uni-versity, Sokoto. Documentation of Solar Energy Systems Developed and Readyfor Mass Production.

Sambo, A. S. (1992): 'Renewable energy resources in Nigeria', Energy Issues inNigeria: Today and Tomorrow (Seriki, O.A. and Adegbulugbe,A.O.(Eds.)), Pp.36- 62, Gilspar Press.

Sambo, A. S. and Doyle, M. D. C. (1986): 'Estimation of the global and diffusecomponents of solar radiation for some Nigerian cities', Nigerian Journal of SolarEnergy, Vol.5, Pp.16 - 24.

World Energy Council (1993): Energy for Tomorrow's World. St.Martins PressInc., New York.

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ly, the close relationship bet- Renewable Energy For Rural Development … · A. S. Sambo /ISESCO Science and Technology Vision - Volume 1 (May 2005) (12-22) 13 2. Some Major Energy